Tandy 1000 SX

Released in 1987 the Tandy 1000 SX was an evolution of the original Tandy 1000 which itself was a clone of the IBM PCjr. The Tandy 1000 line featured several advantages over standard IBM compatibles of the time such as built-in “Tandy video” which offered CGA video modes along with 160×200 and 320×200 16 color modes. The Tandy 1000 also offered enhanced Tandy 3- voice sound. Both Tandy video and audio were very widely supported in games.

The 1000 SX is an enhanced version of the original Tandy 1000 offering many improvements that more or less correct every issue that the original Tandy 1000 had such as making upgrading and expanding the PC easier and adding a faster CPU “turbo mode” as well as a DMA controller to speed up certain processes. Many retro PC enthusiasts consider the Tandy 1000 SX one of if not the best bang for your buck IBM compatibles of the 1980s.

The 1000 SX case when compared to a IBM PC is noticeably smaller which saves desk space. It’s also mostly made of plastic which also makes it a significantly lighter PC. The SX came stock with dual 360k 5 1/4 floppy drives in its dual 5 1/4 bays though the built-in floppy controller also supports 720k drives. We will detail the process of upgrading to one of these larger capacity drives later in the article.

At the bottom of the front of the case there are two screws on the far left and right. Removing these is all that is necessary for removing the cover. On the bottom left of the front we have a large red reset button. Next to this we have a keyboard port. The Tandy 1000 SX uses a proprietary style keyboard port like most of the early Tandy 1000 line. This port is not compatible with standard IBM type PC/XT/AT keyboards so a Tandy keyboard is required though there are modern adaptors that allow the use of standard PS/2 keyboards.

To the right of the keyboard port are dual round 6-pin joystick ports. These joystick ports are also proprietary and require joysticks compatible with the Tandy 1000 and Tandy color computer line.

Turning the Tandy 1000 SX around and we can see the various rear connectors. The power switch like the one on the IBM PC/XT/AT is on the rear left side though the switch itself is not visible in this image. Starting from left to right we have a standard 3 prong connector for the power cord. Next is a card edge style connector located directly under the model label. This is actually an edge-style parallel port and is intended to be used with specific Tandy printers. Adaptors were made to connect non-Tandy parallel port devices to the edge connector. Next is the seldom if ever used DE-9 lightpen connector followed by the built-in video and audio jacks.

First up is a standard DE-9 connector for connecting to TTL RGB monitors. Tandy made several Tandy specific monitors of differing quality like the CM-5 that I’m using and the higher quality CM-11 but any standard CGA type monitor will work. The video output of the Tandy 1000 SX is based on the video capabilities of the failed PCjr but since the PCjr failed this video standard became known as TGA or Tandy Graphics Adaptor. The Tandy 1000 SX can output standard CGA as well as the TGA modes which allow 16 colors on screen at one time. This more or less resembles the look of EGA in low resolutions though they are not the same.

Tandy playing EOB in CGA mode

Tandy playing EOB in TGA 16 color mode

CGA compatibility on the Tandy 1000 line is almost 100% and is CGA register compatible though due to slight differences in text characters used very few games (ex. ICON : Quest for the Ring and The Seven Spirits of RA) may show some minor graphical issues. As for the extended TGA modes available the Tandy 1000 also supports 160×200 with 16 colors, 320×200 with 16 colors and 640×200 with 4 colors out of the palette of 16 colors. A very significant number of games do support Tandy 16 color graphics. Some of these games allow the user to choose the color mode between CGA and TGA but some games will automatically detect if a Tandy is present and force 16 color TGA mode. Some games such as ArcticFox only support 16 color mode via the Tandy graphics adapter.

Next up we have the RCA style A/V jacks for video and audio. At first glance it looks like stereo audio jacks but the red jack is for color composite out for connecting usually to a TV but also to some monitors. Some games may also show differences in colors when displayed in color composite mode on a Tandy 1000 as opposed to an IBM compatible CGA card.

The audio out is very useful if you don’t want to output sound through the internal speaker and instead wish to use an external speaker. The audio out though is disabled by default and some games may fail to initialize. there is a program called  tdyspkr.com which should allow you to select the A/V audio jack as active on boot up for those programs which fail to see it.

Since we are talking about sound It’s worth mentioning the Tandy 1000 SX “Tandy sound” which is a bit more advanced than the standard PC speaker and uses 3 voice channels and 1 sound channel is a clone of the PCjr sound. Tandy sound or Tandy 3-voice sound as it’s also known is generated by either a SN76496 or NCR8496 Chip. Some games such as Thexder only support PC speaker or Tandy speaker sound with Tandy sound being noticeably superior and less grating on the ears. If you opt to not use external speakers Tandy 1000 SX also sports a nice sounding large cone speaker at the front of the case

Removing the case to get inside is relatively easy and only requires removing two screws located on the front face of the case.

Image was taken before math co-processor and memory upgrade

The only expansion card for my Tandy 1000 SX is an I/O card for a serial and parallel port and this is the only card that was installed in this machine when I received it. The metal bar going across the motherboard from the side to the dual 5 1/4 bays is actually a support beam that is easily removed. Its purpose is to help support a monitor if one is placed on top of the case as was a common practice of the time.

Removing the dual 360k 5 1/4 floppy drives gives us a better view of the motherboard.

Like the original IBM PC the 1000 SX only has 5 8-bit ISA slots. Unlike the IBM PC though, the Tandy 1000 SX has the floppy drive controller as well as the video built-in. The motherboard of the 1000 SX also has a built-in DMA chip to speed up certain processes, something the earlier Tandy 1000, 1000A and 1000 HD lacked.

1) CPU – The 1000 SX uses an 8088 like previous models although the SX runs default at 7.16MHz with the ability to downclock to 4.77MHz for compatibility with older software. The SX has no turbo button so to slow the CPU back down to 4.77MHz you need to use the DOS commands “MODE SLOW” and “MODE FAST” in order to switch speeds. The default speed is 7.16MHz though at boot up you can also press the F4 key on the keyboard to boot into 4.77MHz slow mode. The MODE command which sets the CPU speed is only available in the OEM version of Tandy DOS 3.x.

2) Math Co-Processor – The SX does have a socket next to the CPU for adding a math co-pro. I elected to add an 8MHz capable 8087-2. Adding a math co-pro is hardly necessary and only a handful of programs and games from the time can take advantage of it.

Next to the CPU is a small switch box. These switches can be used to disable several features mostly for the purpose of adding discrete cards. All switches are set to “on” by default. switch 1 disables the built-in video. Switch 2 controls the IRQ the built-in video uses. Switch 3 disables/enables the internal floppy controller and lastly switch 4 will enable/disable the parallel port.

3) RAM – By default the 1000 SX came with 384k of memory but is easily upgradable to a full 640k of memory. My 1000 SX only came with the original 384k of memory but I upgraded to the full 640k via eight 256k x 1 150ns (or faster) DRAM chips. After adding the additional memory jumpers E1 and E2 also need to be removed for the system to detect the change.

640k should be enough memory for any game that will run well on the SX and there is even evidence that expanding past 640k on a 1000 series can cause issues and incompatibilities with games.

4) System ROM BIOS / Smartwatch Battery – This socket is used for both the system BIOS chip on the SX as well as the battery which holds time for the system clock.

System ROM BIOS

you’ll notice that on my machine the BIOS chip is in a socket that is a little high. that’s because my SX has a separate battery module in between the motherboard socket and the BIOS ROM. I don’t believe all SX’s have this module but mine does. its purpose is to hold the date which needs to be entered every time Tandy DOS 3.x loads up on boot. To access the battery you have to first remove the ROM chip which is socketed over it.

You can still purchase a modern replacement for this battery HERE which allows the use of a coin-style battery.

5) Speaker Volume control – Unfortunately there is no way to control the volume of the speaker from outside of the case but Tandy did include a volume adjustment on the motherboard. If turned down all the way the speaker can be completely muted.

6) floppy connector – Built-in connector for connecting floppy disk drives to the SX. The built-in controller supports both 360k 5 1/4 disk drives as well as 720k 3 1/2 style disk drives.

7) Tandy sound chip – As mentioned earlier the Tandy 3-voice sound is generated by either an SN76496 or NCR8496 Chip. For the Tandy 1000 SX it can be either chip. My SX uses the NCR8496 which is a clone of the original Texas Instruments SN76496 chip.

It is almost a perfect clone though there are slight audible differences in the noise channel. I suppose since it’s socketed an original SN76496 could be sourced and swapped out with the clone chip. If you are interested more information on the sound chips can be found HERE.

UPGRADES

There are common upgrades that apply to most all PC and XT machines such as an NEC V20 for a small speed boost or XT-IDE adaptor. There isn’t any place to really mount a hard drive and I use a XT-IDE compact flash adaptor myself which works well. I am using a 32MB card with Tandy DOS 3.2 installed but DOS 6.22 with a larger CF card works just as well.

A hardcard or hard drive on an ISA a card would be a more period correct, though slower option.

I don’t recommend adding an EGA or VGA video card to the SX though you certainly can I just find the whole point to using a machine like this is to take advantage of the Tandy sound and video that so many games supported.

A serial card or bus mouse card could also be useful if you are planning on using a mouse with your Tandy.

I did however add a Sound Blaster 1.5 w/ CMS chips. I’ll be using this machining mostly for older titles that support PC speaker or Tandy sound only though I wanted the option for games that do support digital sound and or adlib/CMS sound.

The upgrade I would definitely recommend is replacing one of the 360k 5 1/4 floppy drives with a 720k 3 1/2 drive. I replaced my drive B with a 720k drive as opposed to drive A since the primary format of the time was 360k disks and thus many “booter” type games came in that format which may require being read from drive A. Since there are no 3 1/2 size bays on the SX case you will need a 5 1/4 to 3 1/2 bay adaptor. Keep in mind you can press the F3 key on bootup to swap the A and B drives.

Some things to consider when adding a 720k drive is that the cable the SX uses is very short and also uses edge connectors so it’s very likely you will need some kind of adaptor and or extension to reach for the floppy drive or you’ll need to use a different cable altogether.

Original 1000 SX floppy cable.

Another thing to keep in mind is the Tandy 1000 SX uses floppy cables without a twist in them so you will need a 720k floppy drive with jumpers that allow you to designate what drive it is.

D0 designates the drive as drive A while setting the jumper to D1 sets the drive as the B drive.

If you can’t find an adaptor and or extension which allows you to use the original short floppy cable that came with the Tandy 1000 SX you will either need to find a longer floppy drive cable without the twist or modify a more common “twisted” floppy cable by untwisting the cable as seen below.

Unfortunately, I had no luck getting my modified cable to work though I know others have. I did end up finding an edge connector adaptor that also had an extension cable attached to it which allowed me to use the original cable that came with my SX and everything works fine.

So is the Tandy 1000 SX a great computer for 80’s PC gaming? I’d say so and I would at the very least say it was one of if not the best value for the money at the time. The built-in Tandy sound and video were far superior to PC speaker and CGA common at the time and many, many games supported the standard. There are a number of games that are just best experienced with Tandy color and or sound. You could have bought an EGA card but those would have been quite expensive and sound cards weren’t really supported until the late ’80s. The option to run the CPU at both 7.16MHz and 4.77MHz for compatibility is also a nice bonus. The 1000 SX is also lighter and takes up a little less desktop space than comparable IBM models and as mentioned at the beginning of the article the SX fixes most of the issues that hampered the original Tandy 1000. I like the Tandy 1000 SX so much I’ve actually replaced my primary 8088 based XT PC with it despite that machine still holding a few advantages over the Tandy.

Tandy 1000RL HD

In some of my earliest articles I covered a few iterations of the popular Tandy 1000 line. The Tandy 1000A as well as the Tandy 1000HD and the compact Tandy 1000 EX and HX but now I’m going to shift to the end of the true Tandy 1000 line and talk about the Tandy 1000RL-HD the last of the 1000 line to be truly PCjr compatible.

As you can tell right away the 1000RL is a slim-line design and the machine is surprisingly light. You have a power button to the far right with a 720kb 3 1/2 floppy drive seated next to it. There is another bay for a second floppy drive but I don’t think a dual floppy RL version was ever sold, though I could be wrong. My model is the hard drive version which is slightly upgraded from the regular RL. You can tell easily which version your getting via the faceplate.

Both the RL and RL-HD come with a 8 bit IDE interface on the motherboard for a hard drive. This is the same style interface as found on machines like the Commodore Colt and in all honesty is not terribly useful. The drives are fairly uncommon and less then 40MB in size. My machine came with the original 20MB Seagate ST325X drive. The drive is very loud powering up and can be unreliable.

The HD version of the RL besides sporting a hard drive stock also has a battery-backed real time clock chip on the motherboard which the regular RL lacks.

The rear of the machine has two levels of ports.

On the far left we have a standard power port for a three prong power cord. Starting on the top left we have a serial port followed by two Tandy 1000 joystick ports, a stereo audio jack for speakers or headphones and a mic jack. Lastly on the top level we have a volume knob for the pc speaker which is a very nice addition. I think the knob would of been better placed on the front of the machine somewhere but its inclusion anywhere is always welcomed.

On the bottom row starting from the left we have a standard CGA port which will output CGA and of course Tandy Color Graphics or TGA as well as monochrome. The 25 pin printer port looks standard but unfortunately it supports no input so its basically a printer only port. Finally we have two ps/2 style ports. Now I say style because of the keyboard port. The mouse port is basically a ps/2 port and depending on the driver used you can get many ps/2 mice to work just fine. I was able to get a more modern ps/2 laser mouse working fine with Cutemouse drivers. The keyboard port though is not quite standard even though physically speaking it is ps/2 compatible. This machine requires an XT keyboard with a ps/2 style connector like the Tandy Enhanced Keyboard that came with this machine.

Otherwise you would need to find a XT keyboard and use an adaptor of some sort.

There is only one 8 bit ISA expansion port available on the rear of the machine making expansion very limited. On the question of adding video or sound cards, you may also of noticed the 1000RL lacks a composite port that was present on earlier Tandy 1000’s. Adding a CGA card with a composite out could be an answer to this issue though. On the sound card front keep in mind that using a Sound Blaster 1.0 or 2.0 may cause freezing under certain circumstances due to conflicts with devices using DMA 1.

The best option in my opinion for the expansion slot would be some kind of 8 bit IDE hard drive controller.

The case is relatively easy to remove and only requires the unscrewing of two screws.

The motherboard for the 1000RL is very compact. It’s basically a laptop sized board in a desktop case. This machine also has Tandy Deskmate and DOS 3.3 built into ROM so a hard drive is not needed to boot up and then access a floppy disk which is very nice.

Video – The video on the Tandy 1000RL uses an enhanced version of TGA known as ETGA which has all the old modes of the TGA plus a 640×200 with 16 color mode

1) Pc Speaker

 

2) riser card – this card contains the rear joystick ports, serial port and audio jacks as well as the volume knob. It is connected to the main board via a connector. The chip directly in front of the riser is I believe the PSSJ chip which controls the audio and ports on the riser.

 

 

3) CPU – the 1000RL CPU is an AMD 8086 running at 9.56mhz though there is an option in BIOS to set the speed to 4.77mhz or by typing “MODE SLOW” in Tandy DOS and “MODE FAST” to return to 9.56mhz. As I’ve mentioned before the 8086 in most circumstances performs faster then the 8088 at equivalent speed so some old game MAY have issues. This speed can be a benefit though for some games such as Digger that may run a little to slow on something like the PCjr. The CPU though is soldered onto the motherboard and not socketed thus it is impossible to replace it with a NEC V30 for more speed.

 

 

There is also no socket on the motherboard for a 8087 math co-pro but since hardly any games take advantage of one this isn’t much of an issue.

 

4) RAM – The standard RAM on the RL is 512kb but this can be expanded to 768kb (640 DOS, 128kb for video) via two 256k x 4 DRAM chips.

 

5) The regular 1000RL has a socket for an added real time clock but the RL-HD has one built into the motherboard using an easy to replace lithium coin battery.

 

6) One 8-bit ISA slot.

 

7) IDE-XT Interface – Both the RL and RL-HD have a IDE-XT 8-bit interface built into the motherboard. This interface only works with a small number of hard drives all being under 40MB.

 

8) Floppy Interface – The non standard floppy interface is typical of Tandy and supplies the power via the floppy cable to the drive.

 

9) PSU

 

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The Tandy 1000RL-HD has its problems. The built in HD interface was a dead end and there are some minor game incompatibilities but overall it makes a good Tandy machine. It supports TGA graphics as well as 3 channel audio sound and has a slow enough CPU to play most of the games that support those options just fine. Its also extremely light and small taking up little desk space. The fanless design means without a hard drive or when using a CF as a hard drive the machine is dead quiet and invites very little internal dust. The fact that DOS and Deskmate are present in ROM also alleviates some issues such as always needing a DOS boot disk handy to get into the system. They seem to be fairly common and reliable models so if you can find one for a low price its a no brainer to pick it up.

Tandy 1000 HD

At first I was just going to roll this article in with my Tandy 1000A article I did awhile back but after more research I found out there wasn’t a whole lot of specifics out there on the 1000 HD so in the end I think it deserved its own post, even if it is a rather short one.

The Tandy 1000 HD looks pretty much identical to the standard Tandy 1000 and 1000A. The HD doesn’t stand for “high definition” but “hard drive” and as a matter of fact before I got this unit I just assumed it was a Tandy 1000  with a hard drive and controller card slapped inside by the factory….and it is but at least they went through the effort of badging it differently as well as add a ram and DMA card (at least I think the ram/DMA card are stock from the factory.

Simplest way to tell its a 1000 HD, check the badge on the front

As we can see from the back the 1000 HD uses the same wattage power supply as a 1000A and I assume 1000. If you look on the right at the expansion slots you can see the cards are sticker labeled. The middle card is a modem which I don’t know if it was added later or came standard from the factory but the memory PLUS card does specifically say Tandy 1000 HD so I suspect it came stock with the hard drive controller card which would make sense as The extra memory and DMA controller would be very helpful with an added hard drive. All the other ports are same as on a stock Tandy 1000.

Here is the machine after being opened with all three expansion slots filled. Notice the massive hard drive circa early 1980’s. Its so large that they had to install it parallel with the case rather then a more traditional bay setup. These drives installed factory were in the 10 to 20MB range. I don’t have a Tandy keyboard at the moment (you need one, its a proprietary keyboard port) so I couldn’t do much checking. On powering mine up it gives a boot screen and a memory check of 640kb but then nothing so I assume my floppy drive and hard drive are dead. My motherboard and power supply seem in fine shape though.

Here we have the motherboard with the expansion cards removed. Comparing images It seems to use the exact same motherboard as the standard Tandy 1000 and you can see no slot for a 8087 next to the CPU. Mine seems to have a rather low serial number so I’m not sure if later models of the 1000 HD used the improved 1000A motherboard but from what I could find they do not. I could not fully remove the hard drive and floppy drive cover and holder because one screw is particularly hard to get if not impossible with standard tools unless I wanted to go through a lot of trouble or damage the brackets securing the hard drive so I left it alone. I assume Tandy expected you to ship the unit back to them if you ever decided to replace the hard drive.

Now for the two important expansion cards that I believe must of came stock with this PC to facilitate the added hard drive.

Here we have the 8-bit hard drive controller card. A Western Digital wd10025-wx2 controller card. the Bios “G” version of this card can handle 10 and 20mb hard drives as seem stock on the Tandy 1000 HD but cards with a “H” Bios can handle drives up to 62MB in size. Its not a proprietary controller card so you could potentially pull and use this controller in any old PC you have that requires an 8-bit hard drive controller for MFM drives.

Lastly is the Tandy memory PLUS expansion card. This card bumps the RAM up to 640kb and adds a DMA controller or “Direct memory access” controller to greatly help speed up hard drive and various other operations. I believe the pins in the lower right hand of the card are for an optional RS-232 serial port expansion.

Finally we have the Tandy 300 baud modem. I don’t really mess with old networking and what not so not much to say about it.

I would say if you can find one of these machines for a reasonable price or free the 8-bit hard drive controller alone is worth the effort not to mention the nice Tandy memory expansion PLUS card. A fully working system would also make a nice vintage gaming machine for the early era of PC gaming plus you get a hard drive and that great Tandy graphics and sound.

Odds & Ends: TRS-80 Model 100, Iomega Zip drives, Gravis gamepads

In this Odds & Ends I’m going to go over the venerable TRS-80 Model 100 a small portable computer. Also the much more successful relation of the LS-120 super drive the Iomega Zip drive and finally a number of gamepads from the king of PC gamepads in the 90’s, Gravis.

TRS-80 Model 100

Considered the worlds first laptop computer I came across my model 100 at a Goodwill and purchased it for a couple of dollars, about $3 I believe and to my surprise on hitting the power button the thing turned right on.

As you can see the model 100 is sort of like a giant calculator. These machines began to be sold back in 1983 and have anywhere from 8kb to 32kb of RAM. I believe mine had 24KB installed. Apparently these machines were very popular with news journalists and other “on the move” individuals. As I am primarily a gamer and this machine is pretty obviously not a gaming machine I don’t have to much to say about it but I did think it was kind of a neat little find. It has no internal mass storage capabilities so for saving anything permanently you would need to use an external cassette player of disk drive. The screen is a non backlit LCD and despite the age it displayed quite clear for me. I’m going to go out on a limb here and say that its probably only capable of text display. It is also powered by 4 AA batteries but also has a port for an external 9v dc power supply. I’ve read that it is very easy on batteries and can go for 16+ hours on batteries.

Here we have the back of the computer with most of our ports. We have a small reset button as well as a RS-232 serial port and printer port. The north American version like this one has a built in 300 baud modem which I believe that phone port may be for. Lastly a cassette port for a cassette player for storage.

Other then that I don’t have much to say about it. Its a neat little machine but doesn’t have much practical use I can find today at least not for myself. Apparently this machine has quite a following though http://www.club100.org/

Iomega Zip drives

Ah, the Zip drive. The much more popular “floppy” storage alternative to the LS-120. The Zip drive’s initial version could store up to 100mb of data on a disk and eventually a 250mb and 750mb version was released. Unlike the LS-120, Zip drives cannot read or write to standard 1.44mb floppy disks but they do have a higher transfer rate to their disks then a floppy has to its own. I’ll admit the Zip drive has become indispensable to me lately as everything from DOS to windows 7 supports it. Although smaller in storage capability They are more convenient then burning CD’s. Its nice to be able to download a patch or file from your internet connected Windows 7 PC that may be a little to big or to many files for a standard 1.44mb floppy. Transfer it on a Zip disk and then easily transfer that file to you ancient 286, 386, 486 or whatever PC. With a cheap and advisable NEC V20 CPU upgrade the Zip DOS driver even works on 8088 based PC’s like the original IBM 5150 via a parallel port. I even believe Zip disks are Macintosh compatible (may require mac formatting or only certain models). I personally tend to stick with the 100MB models as the larger capacity models seem to be rarer and more prone to failure as well as not being fully backward compatible. Also 100mb tends to be more then enough storage capacity for my pre USB capable systems.I believe zip drive drivers are included with Windows XP and 7. At least I had no trouble connecting my external USB drive to my Win 7 machine. There are separate drivers for Windows 98 and DOS. I don’t generally link to drivers here but I can tell you they aren’t hard to find with a web search. you can try the Vogons driver database here and check under uncategorized or utilities for the relevant drivers. The DOS drivers should fit on a 1.44MB floppy and all you need to run is Guest.exe and it will assign a letter for your zip drive. You can set it to do this on boot though your .BAT file but I generally just have it in a file named “ZIP” on my hard drive and only use it when I want to use the Zip drive since the TSR does eat some DOS memory when active.

I’ll start off with the internal drive. The internal drives came in two flavors, IDE and SCSI though the SCSI version seems to be far more uncommon.

Here we actually have a 250mb model which is identical except for storage capacity and logo to the 100MB model. I’m using this particular drive since all my other internal drive are install in systems at the moment. The internal drives are the same 3 1/2 inch size as a standard 1.44MB drive so you can install them anywhere you would one of those. Like most this is an IDE version and connects to an IDE controller just like your standard hard drive or CD-ROM drive. Being IDE it also has a jumper for Master, Slave or Cable Select. Many BIOS’s from the mid 90’s up directly support Zip drives. The thing that I find slightly annoying is the use of a larger molex power connector used for larger devices such as hard drives as opposed to the smaller floppy power connector. Usually that means I have to dig out or buy a Molex splitter because I’ve already used up all my connectors on hard drive and CD drives.

Here we have the uncommon SCSI version of the internal zip drive. These were most likely intended mostly for Macintosh users. The front bezel is a little different and as you can see on the back it uses the smaller floppy drive style power connector as the 50 SCSI connector is larger then IDE. You also have jumpers to set device ID number and SCSI termination.

Now I’ll move on to the more common and cheaper external drives which happen to come in many flavors from USB and Firewire to SCSI and parallel and possibly others. These drives require and external power supply but other then that are identical in function. I tend to see these external drives fairly commonly at Goodwill’s and thrifts at a decent price. About $9.99 but sometimes under $5.

This is my USB external zip drive that I use with my Windows 7 machine. The see through blue plastic shell is kind of cheap looking and it kinda clashes with my black PC but it works like a charm and was as simple as plugging in the power and USB cable and then it just works.

Here is an assortment of older external parallel port and SCSI drives. On the far left is a Epson branded 100MB parallel port zip drive. The parallel port drives are very versatile and will pretty much work with any IBM PC or clone with a parallel port all the way back to the 8088 based models provided there CPU is upgrade with a NEC v20 chip. I believe this is because the V20 does contain some later coding that the 8088 lacks but which the Zip drive needs to function. As far as I know these are identical in function to the Iomega drives except for the branding and the color. I prefer the off white color of the Epson models as it looks much better with the off white case coloring of 1990’s and earlier PC’s that I generally use it with. The middle drive is a Iomega branded SCSI Zip drive. Finally on the far right is a 250mb model which uses a parallel port.

Here are the parallel port and SCSI port drives from the rear. The parallel port drive is pretty simple with a input and then a pass through for a printer or potentially any other parallel port device. The SCSI drive has a few switches though. One is to set termination either on or off. On a SCSI chain of devises you want a “terminator” device on the last connection in the chain or have the last device on the chain set as a terminator. It also has a switch to set the device number ID for the SCSI chain. The SCSI Zip device can only be configured as ID 5 or 6. Also take not that the Zip SCSI drive uses the same 25 pin SCSI connector found on many Macintosh’s. Your going to want a 68 pin adapter like this one if you want to use it on most later PC SCSI controller cards.

All in all I’m a fan of Zip drives and they’ve been a major convenience for me in transferring files. If your making a retro rig I do strongly suggest at least keeping a external model handy.

Gravis Gamepads

Back in the 1990’s Gravis was known for their Gravis Ultrasound sound cards for PC’s. Sound cards largely seen as superior in sound quality to the Creative Sound Blaster line but they also made a line of very successful PC game pads. Although their sound cards never became the de facto sound standard there game pads for the most part did. I have a few Id like to go over here. Keep in mind this is a evolving article so as I acquire more I’ll be sure to add them.

This I believe is the first model introduced labeled just the Gravis PC gamepad. I do believe there were a few minor variations. It has a standard D pad as well as a little joystick part that you can actually unscrew. This pad is very common and I see them at thrifts all the time though usually the joystick part is either missing or broken off. These make really nice DOS gamepads for games that support joysticks/gamepads. I like to use them for first persons shooters like Doom or Duke3d or platformers like Bio Menace. No drivers needed just plug it into your gameport either built in or on your sound card. As long as your game can be configured to use a gamepad it should work.

This is the Gravis Gamepad Pro which is also a fairly common gamepad. This pad is a little more modeled on console controllers and bears a resemblance to the playstation controller. The gameport connector on this model is a pass through so you can connect a second gamepad for two player gaming. Other then that its basically the same as the standard gamepad though it does sport a start and select button as well as four more buttons on the shoulders. I generally prefer this controller and this is what I generally use for games like Doom or Duke3d.

Here we have the Gravis Destroyer. In most ways this is kind of a step down from the Pro controller. I think its a little more comfortable to hold but it has less options. Less buttons including the lack of the start and select buttons, no joystick knob and the port connector is not a pass through so forget two player. It does sport a turbo button and LED that lights up green when activated which seems like a handy feature for shoot em ups. This controller does seem slightly less common “in the wild” and as the others is a breeze to use in DOS.

The Gravis Xterminator. To be honest I don’t know much about it since this is a digital gamepad and as far as I can tell does not work in DOS. Maybe it will with drivers but from my initial search I could not find drivers for DOS or its intended OS Windows 9x. This controller does sport a lot of buttons as well as a analog joystick. It also has a pass through connection to allow other gamepads to be connected which is nice. I’ll keep looking for drivers this controller and update this article once I find them.

Lastly I have a USB Gravis Gamepad Pro which is basically just a straight USB version of the standard gameport gamepad pro so in all areas besides the interface it is identical. This is a basic but excellent gamepad and since it uses standard windows joystick drivers it should be just plug n play for windows 95 and up. I frequently use this controller on my Windows 7 machine for arcade emulation and it makes a great and simple gamepad that you simply plug in and it works.

Gravis was a defining force in 90’s PC gamepads and I highly recommend at least the gamepad or preferably the gamepad pro for all your DOS game padding needs.

Tandy 1000A (and how to identify one)

The Tandy 1000 line of computers was a pretty important and well known computer line of the 80’s. Based off of IBM’s failed PCjr It had superior sound (Tandy 3 channel) and video (Tandy graphics which was a improved version of CGA looking very similar to EGA) when compared to other IBM PC’s of the time that used a PC speaker and CGA or Monochrome graphics. If you want to learn more about the details or Tandy graphics there are tons of informative pages on the net and I would suggest starting at Wikipedia or here. I recently acquired a Tandy 1000A for about $10 with an accompanying Tandy  CM-4 RGB color monitor (just an older version of the CM-5 but basically identical). So what is the Tandy 1000A and how is it different from the original? Cosmetically and functionally they are pretty much identical except that according to Wikipedia the 1000A “fixed bugs, scanned expansion cards for bootable ROMs, and added a socket for a math coprocessor”. Since there is already so much information on this particular computer and not a whole lot for me to add I’m just going to briefly go over it here and point out the differences between the original Tandy 1000 and the slightly later 1000A revision so you know which one you have.

unfortunately the Tandy 1000A I bought did not come with a keyboard and I suspect both 360K 5 1/4 floppy drives no longer function. To speak for the Tandy’s build quality I purchased 2 other computers at the same time both mid 90’s Pentium 1 rigs. They both failed to boot (most likely a power supply issue) while the Tandy booted right up. The front is identical to a stock Tandy 1000 even down to the name plate. you have the two disk drives, big red self destruct button…errr reset button. a keyboard port proprietary to the Tandy so you cant use a standard IBM keyboard and finally two joystick ports. The power switch is on the right hand side at the rear.

The back is also identical for the most part to a standard 1000. from left to right we have the parallel printer port, light pen port (not a serial port and pretty much useless) and RGB monitor port (for CGA monitors), composite a/v out in case you don’t have a monitor you can use a TV set and finally a mono audio a/v out.

also on the back we have the first and easiest way to see if you have a 1000A.

Take a look at the model number written above the boxed serial number. If it says 25-1000A then you have a 1000A….most likely. It is possible that someone at some point damaged the case and swapped motherboards putting a 1000 MB into a 1000A case. If you want to be completely sure we need to open it up and look inside. Fortunately this is incredibly easy and requires removing 5 screws, 2 in the front and 3 in the back.

(click to enlarge)

Here we have the motherboard, usually the entire right side is obscured by the power supply, floppy drives and aluminum casing which I have temporarily removed.

1) This is the empty slot for an optional 8087 math co-processor. This slot will not be present on a standard Tandy 1000 and was the biggest obvious addition to the 1000A. The addition of a math coprocessor would speed up the computer when running some programs and math intensive applications.

2) This is the 8088 CPU of the 1000A, the same CPU as in the 1000. The CPU runs at 4.77MHZ (or 4.6 by some independent benchmark tests) and can be upgraded to a NEC V-20 chip to improve performance (only works in about 70% of Tandy 1000, 1000A’s). I plan to go into more details at a later time, perhaps if a do an “Anatomy of” feature on the Tandy but as of now I’m just going to quickly go over the basics.

3) connection for the power supply. it looks like AT but i believe it is proprietary.

4) this is the floppy connector for the two 5 1/4 floppy drives.

The Tandy 1000A like the 1000 comes with 3 8-bit ISA slots.

This a single slot 8 bit ISA memory card for the Tandy.  It has 512k of RAM on board bringing the total system RAM to its max of 640k. This card also has a DMA chip or (Direct Memory Access) on board increasing IBM compatibility. Later versions of the 1000 like the SX had the DMA chip as well as the potential 640k of RAM on the motherboard itself.

The Tandy 1000A is a slight upgrade from the stock 1000 and is not difficult to differentiate once you know what to look for. In the end though it pales in comparison to the later SX, TX and even the compact EX/HX Tandy 1000’s which offer much more expandability and features while maintaining the same compatibility for the early Tandy era games and applications.

Tandy 1000EX and 1000HX (its raining Tandys)

picked up Tandy 1000EX system in great condition with the boxes. I still like my Tandy 1000 SX better but at least this model has a volume control for the internal speaker. it also came with the 640k ram expansion and a modem, I never use modems in these old computers though. The main attraction to the Tandy series of computers is there almost perfect IBM compatability but also with the improvments introduced with IBM’s PCjr such as Tandy Graphics and improved sound.